A worker paints yellow over the blue at one of Moscow’s Stalin-era skyscraper with a star on top, which was painted in colors of Ukrainian national flag in Moscow, Russia, Wednesday, Aug. 20, 2014. (AP Photo/Ivan Sekretarev)

MOSCOW (AP) — Protesters on Wednesday scaled one of Moscow’s famed Stalin-era skyscrapers and painted the Soviet star on its spire in the national colors of Ukraine. The dangerous prank, which set Russian social networking sites abuzz, drew a harsh response from the police.

The protesters also attached a yellow and blue Ukrainian flag to the top of the 580-foot building east of the Kremlin along the Moscow River.

Russian authorities were not amused by the expression of support for Ukraine, where government troops are battling pro-Russian separatists. Police said they detained four suspects and charged them with vandalism, a crime punishable by up to three years in prison.

In Ukraine, President Petro Poroshenko welcomed the raising of the flag on the Moscow skyscraper, calling it a “symbolic” gesture. In a video address, he urged Ukrainians all over the world to fly the flag at their homes and offices ahead of Independence Day on Sunday. The holiday celebrates Ukraine’s 1991 independence from the Soviet Union.

The LifeNews media site posted a video that it said shows one of the protesters parachuting off of the building shortly after dawn and landing in an inner courtyard.

Russian news agencies, citing police, said the four suspects had climbing equipment with them when they were detained.

By midday, the star with the Soviet hammer and cycle had been repainted gold.